Both "Betamax" and "VHS" videotape cassettes include a takeup roller which typically is an injection-molded plastic sleeve rotatably mounted on a fixed, machined stainless steel pin. Because it is impractical in large-scale molding of the plastic sleeve to maintain an exacting inner diameter, rotation of the plastic sleeve would often create undue mechanical noise unless a heavy grease were applied to the stainless steel pin. The use of grease not only involves a contamination problem, but a significant proportion of videotape cassettes must be rejected because the takeup roller is either overgreased or undergreased.
Even though stainless steel can be virtually nonmagnetic, such a pin may be sufficiently magnetic to cause slight degradation of signals in magnetic recording tape moving across a plastic sleeve which is rotatably mounted on the pin. Accordingly, a plastic pin would be preferred, but even if the pin were machined after being molded, it would increase the range of clearances between the plastic sleeve and its pin and hence would result in a higher rejection rate due to under or overgreasing. On the other hand, if the steel pin could be replaced by a molded plastic pin without exacerbating such problems, the cost of the roller-pin assembly could be substantially reduced.